Methods of cancelling postage stamps affixed to envelopes passing through modern postal sorting facilities involve the rapid, automatic feeding of envelopes, letters and the like in singular file, termed singulated mail, with the envelopes passing vertically along a conveyor system with the stamp-bearing faces of the envelopes facing the same way with the stamp to be cancelled located at an upper corner thereof.
In such a stamp cancelling system, the address and postal code are read by, typically, face reading means such as a multiline optical character reader (MLOCR) and a machine readable fluorescent bar code is sprayed on to a front face of the envelope printed either in black, fluorescent or phosphorescent ink at a predetermined area on the face with reference to the lower and leading edges. This is accomplished by detection of the leading edge by optical sensing means and printing of the bar code at a pre-selected height on the envelope.
In both of the above methods, reading of the postal code by the MLOCR enables a pre-programmed sort by automatic reading and memorization of the code and the envelopes to be subsequently sorted into individual sort components of a letter sortation machine (LSM). A LSM may, typically, have 150 or more compartments. The envelope contents of these compartments may then be subdivided, either at the same or different postal site, into a sorted and arranged manner for direct use by the mail delivery person.
In addition to initiating the reading of the postal code by the MLOCR, the leading edge detection means triggers a printer to stamp the envelope for cancellation of the stamp purposes. The printer is set to effect cancellation of the stamp at the expected location of the stamp. However, such prior art printing methods and apparatus operate on the assumption that all pieces of mail, commonly envelopes, are approximately of the same size with their stamps located in the same general region on the face of the envelope, i.e. adjacent the upper right-hand corner. Unfortunately, such stamp location assumptions are not always correct and significant numbers of self-adhesive postage stamps do not get cancelled and the envelopes delivered to individual mailing addresses bearing non-cancelled stamps. In consequence, the stamp may be removed and reused. Also, people are re-using indicia-marked envelopes. Such action has been estimated to cost the national postal authorities significant losses in postal revenues.
A further problem existing in the postal delivery field is the occurrence of disputes between receivers of the mail and mail senders as to the date of arrival at the receiver's mailing address. Such a dispute may arise as between the sender of invoices, bills, legal documents, notices and the like. Thus, the receiver may argue that the document arrived later than it actually did at the mailing address. Accordingly, means of evidencing that the mail processed through the incoming postal processing facility as to time, date, machine used and place of processing and sorting, could provide a very useful solution to this problem. In addition, this would assist in quality control tests conducted by the postal authorities to track and trace mail and provide internal management control. Thus, such a ready means of printing a pre-programmable message or other data on an envelope if readily and cheaply developed could provide significant benefits.